The present invention is related to automotive safety restraint systems and, more particularly, to a low-friction, self-locking latch plate or tongue assembly for a 3-point seat belt system.
Self-locking tongues or latch plates are commonly used to tighten and secure the shoulder and/or portions of a seat belt about the occupant. Such latch plate or tongue mechanisms find application with seat belts for center seats as well as in a continuous type seat belt system having retractors that are commonly used in outboard seating positions. These self-locking tongues or latch plates must be capable of sliding on the webbing in order to provide a proper fit over the occupant and must be able to lock during crash positions to prevent loosening of the lap belt portion and to prevent slack in the shoulder belt portion which may cause a direct transfer of additional forces to the lap belt portion.
In typical operation, the occupant slides the latch plate along the webbing for proper fit. Once secured in place these devices generate sufficient friction to maintain the webbing in place. Upon disconnection of the tongue from a buckle the seat belt retractor will wind up the loose portion of the seat belt webbing. However, due to the inherent friction in many of these prior devices, the latch plate will stop when it reaches the retractor if mounted on the floor; or will stop when the tongue engages a web guide normally mounted to the vehicle's pillar or door at shoulder height. As a result the seat belt webbing is not fully retracted and dangles loose. The loose webbing presents an inconvenience in that it may become caught in the door or cause an entanglement with the occupant. U.S. Pat. No. 4,551,889 presents a self-locking tongue in which the friction between the tongue and the seat belt webbing in its unbuckled state is reduced, thereby permitting the webbing to slide through the tongue during retraction thereof to permit the webbing to become fully retracted thereby elimating the above discussed problems.
It is an object of the present invention to provide a self-locking latch plate having a negligible friction coefficient to permit the seat belt webbing to be fully retracted when not in use. A further object of the present invention is to provide a latch plate wherein some functions correctly with or without an associated cover and lock bar.
Accordingly, the invention comprises: a latch plate assembly comprising: a plate having formed at one end thereof a tongue and at an opposite end a back portion. The back portion comprising open ends and an open recess and including radially extending opposing openings through which may be received a substantially flat seat belt webbing. Lock bar means are provided and moveable between first and second positions for releasing and compressing the webbing. The assembly additionally includes cap means for enclosing the open recess and open ends including guide means for positioning the lock bar means into compressive engagement with the webbing and for slideably securing the lock bar (80) therein.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.